Perturbations in gut microbiota composition in patients with polycystic ovary syndrome: a systematic review and meta-analysis.
Level 4 - case-series / case-control
Systematic review and meta-analysis of observational case-control studies
PubMed 37559119 · doi:10.1186/s12916-023-02975-8
What was done
A systematic review and meta-analysis of observational case-control studies up to May 2023 evaluated gut microbiota differences between pre-menopausal women with polycystic ovary syndrome (PCOS) and healthy female controls. Unreported diversity indices were obtained by downloading and processing raw sequencing data. Methodological quality was assessed with the Joanna Briggs Institute Critical Appraisal Checklist. Hedges g standardized mean differences (SMD) with 95% confidence intervals were pooled for alpha diversity, while beta diversity and taxonomic alterations were synthesized qualitatively.
What was found
Across 28 studies (1022 PCOS patients and 928 controls), PCOS patients had significantly lower microbial evenness (Shannon index: SMD = -0.27; 95% CI, -0.37 to -0.16) and phylogenetic diversity (SMD = -0.39; 95% CI, -0.74 to -0.03). Reported beta-diversity results were inconsistent across studies. Qualitative synthesis identified depletion of Lachnospira and Prevotella and enrichment of Bacteroides, Parabacteroides, Lactobacillus, Fusobacterium, and Escherichia/Shigella in PCOS.
Why it matters
This review resolves conflicting findings across smaller studies, confirming that PCOS is associated with reduced gut microbial diversity and shifts toward pro-inflammatory bacterial profiles.
Limits
All included studies were observational case-control designs, preventing causal conclusions about whether gut dysbiosis precedes or results from PCOS. Heterogeneity was substantial for taxonomic abundance and beta diversity, and the abstract does not report adjustment for major confounders such as body mass index, diet, or medication use.
Cited by
- supports Women diagnosed with polycystic ovary syndrome (PCOS) exhibit an altered gut microbiome and disrupted gut-brain axis compared to healthy controls.